Containers commonly used to package beverages include, for example, polyethylene terephthalate (PET). Those containers, of which PET is one example, may have a number of desirable characteristics, including excellent durability, natural clarity, and low cost. Among drawbacks of some of those containers are that they may not be completely impermeable to some gases, such as oxygen and carbon dioxide, for example. For carbonated beverages, this can be particularly problematic, and the shelf life of those beverages may be limited when those beverages are packaged in such containers. After some period, carbonated beverages may develop a taste that lacks their characteristic fizz and may be considered flat by consumers. The shelf life of beverages may also be dependent upon other gases and may, for example, be related to the ingress of oxygen. Oxidation of materials is important to control in a number of beverages, including juice and beer, among others. In part for those reasons, more expensive containers such as glass or specialty copolymers may be used in containers for some beverages.
In view of those difficulties, a number of strategies have been developed to try to increase the gas barrier properties of containers such as PET. Strategies have been developed that modify the polymers of containers, and a number of co-polymers have been developed that have improved gas barrier properties. Unfortunately, such strategies may be expensive, may adversely modify other positive attributes of PET containers, and may complicate the organization of beverage production lines. There is, therefore, a need for strategies to improve the gas barrier properties of PET containers, methods that achieve such improvement in a cost effective manner, and methods that may be readily adopted in a beverage bottling facility.